Dimethyl sulfoxide

Dimethyl sulfoxide (DMSO) is a widely used solvent that is miscible with water and a wide range of organic solvents. It goes by several names, including methyl sulfoxide, sulfinylbismethane, and dozens of trade names.

DMSO was first discovered in the late 19th century as a byproduct of the kraft process for making paper from wood pulp. About the same time, Russian chemist Alexander Zaytsev synthesized it by oxidizing dimethyl sulfide, another kraft process byproduct. Zaytsev’s synthesis is the basis for the manufacturing process still used today.

DMSO is a laboratory and industrial solvent for many gases, synthetic fibers, paint, hydrocarbons, salts, and natural products. Because it is aprotic, relatively inert, nontoxic, and stable at high temperatures, it is a frequently used solvent for chemical reactions. Its deuterated form is an ideal solvent for NMR spectroscopy.

In the 1960s, scientists observed that DMSO penetrates human skin with little effect on tissues; and the solvent was tested as a way for medicines to be carried into the body as an alternative to oral formulations or injectables. Since then, DMSO has been used in some transdermal drug delivery systems (i.e., patches). In 1978 the US Food and Drug Administration approved it for use for the symptomatic relief of chronic interstitial cystitis (bladder pain syndrome)—the only FDA approval for DMSO as an actual medication.

As one might expect for the 1960s, DMSO was tried as an alternative drug for inflammation relief and as a solvent for introducing illicit drugs such as cocaine into the body. It was also wrongly touted as a cancer cure. In 1965, FDA put the kibosh on much of this activity by banning clinical trials with DMSO because the compound altered the refractive index of eye lenses of laboratory animals. The ban was lifted in 1980 after the intense interest in the substance abated.

Researchers continue to look at DMSO as a possible medical treatment. In 2016, Gerald Krystal and colleagues at the British Columbia Cancer Agency (Vancouver), the University of British Columbia (Vancouver), and Vancouver General Hospital reported that DMSO represses inflammatory cytokine production from human blood cells and thus reduces autoimmune arthritis. The authors also examined whether DMSO has any anticancer activity; they concluded that they could not confirm that it does.